Taxonomic and methodological biases in saproxylic beetles: Body size, trophic group and detection probability

Mustafa Avci
Antoine Brin
Hervé Brustel
Jan Budka
Jörn Buse
Giuseppe Carpaneto
Stefano Chiari
Lukáš Čížek
Mustafa Coşkun
Jeremy Dagley
Peter M. Hammond
Estefanía Micó
Tuba Öncül Abacigil
Tomáš Pavlíček
Jiří Schlaghamerský
Pavel Šebek
Anne Sverdrup-Thygeson
Sakin Vural Varli
Lars Westerberg
Inge Wilde
Agnese Zauli
Graphical abstract : Uncovering biases in beetle biodiversity
Year
2026
Publication type
Peer-reviewed article
Journal
Insect Conservation and Diversity
Pages
1-8
Language
English
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Abstract
  1.  Smaller insect species are routinely described later than larger species,perpetuating the Linnean shortfall.
  2.  Using 425 saproxylic beetle species from 28 veteran oak sites, we test whether body size varied with year of description and earliest georeferenced record year, and whether body length predicted detection probability.
  3.  Linear models show a significant negative relationship between body length and both year of description (β = 0.00063 ± 0.00021 SE, p = 0.003) and earliest geor- eferenced year (β = 0.00057 ± 0.00024 SE, p = 0.016).
  4. Single-season occupancy models reveal only a marginal size effect on detection (β = 0.021, p = 0.055); instead, the trophic group drives variation, with saproxylophagous species detected most readily.
  5.  Fourteen species remain undescribed, and 29% lack any georeferenced record, highlighting combined Linnean and Wallacean shortfalls.
  6. Historical taxonomic bias towards conspicuous species and methodological under- sampling of specific trophic guilds together impede accurate biodiversity assessment.
  7. We recommend integrated taxonomic revision, diversified trapping protocols and trait-based occupancy models to rectify these biases and improve conservation planning.